The present invention relates to optical systems. In particular, the present invention relates to optical systems using a single optical source in data storage devices.
Optical data storage systems access data by focusing a laser beam or other light source onto a data surface of a medium and analyzing the light reflected from or transmitted through the medium. In general, data is stored in optical storage systems in the form of marks carried on the surface of the medium which are detected using a reflected laser light.
Compact discs, which are widely used to store computer programs, music and video, are one type of optical data storage system. Typically, compact discs are permanently recorded during manufacture by etching the surface of the compact disc. Another type of optical system is a write once read many (WORM) system in which a user may permanently write information onto a blank disc. Other types of systems are erasable, such as phase change and magneto-optic (M-O) systems. Phase change systems detect data by sensing a change in reflectivity. M-O systems read data by measuring the rotation of the incident light polarization due to the magnetic state of the storage medium.
In many prior art optical disc storage systems, the optical head is carried on a mechanical actuator which moves the head across the disc surface. In some more recent data storage systems, the optical head is carried on a slider which flies over the surface of the disc and is located at the end of an actuator arm. A significant portion of the optics in such systems is not carried on the armature. Instead, much of the optics is spaced apart from the armature and light from the optics is directed to a slider, for example by directing a beam toward the slider or by using an optical fiber.
An optical data storage system that includes an optical source and an optical storage medium. The system includes a plurality of armatures positioned adjacent to the optical storage medium. Mounted on each armature are elements that perform functions such as beam-splitting, beam-shaping, relaying and fine tuning to collectively form an armature-mounted optical coupling system. An optical switch couples the optical source to each of the armature-mounted optical coupling systems. This configuration of an optical data storage system ensures that one optical source can be utilized for a plurality of optical detection systems.